The huge amount of data speculated to be involved in the hack is seven times the amount that was leaked in the Sony Pictures hack of 2014, which led to then co-chairperson Amy Pascal leaving the company due to emails leaked.

The level of data taken also indicates that audio and video has been stolen, meaning episodes of shows like Game Of Thrones could be leaked online.

Erik Rasmussen, who works at the cybersecurity firm Kroll, told the Hollywood Reporter: ‘At 1.5 terabytes, it could be a whole block of TV, or worse, it could be emails, financial documents, employee or customer information.

‘The fact that you have law enforcement and a [cybersecurity] firm involved most likely means this will be a very large incident for HBO.’